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netfilter: ip6t_NPT: fix IPv6 NTP checksum calculation

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csum16_add() has a broken carry detection, should be:
sum += sum < (__force u16)b;

Instead of fixing csum16_add, remove the custom checksum
functions and use the generic csum_add/csum_sub ones.

Signed-off-by: Ulrich Weber <ulrich.weber@sophos.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Ulrich Weber 2013-01-02 05:24:40 +00:00 committed by Pablo Neira Ayuso
parent fdb184d146
commit 429da4c0b1
1 changed files with 7 additions and 26 deletions
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33
net/ipv6/netfilter/ip6t_NPT.c
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@ -14,42 +14,23 @@
#include <linux/netfilter_ipv6/ip6t_NPT.h>
#include <linux/netfilter/x_tables.h>
static __sum16 csum16_complement(__sum16 a)
{
return (__force __sum16)(0xffff - (__force u16)a);
}
static __sum16 csum16_add(__sum16 a, __sum16 b)
{
u16 sum;
sum = (__force u16)a + (__force u16)b;
sum += (__force u16)a < (__force u16)b;
return (__force __sum16)sum;
}
static __sum16 csum16_sub(__sum16 a, __sum16 b)
{
return csum16_add(a, csum16_complement(b));
}
static int ip6t_npt_checkentry(const struct xt_tgchk_param *par)
{
struct ip6t_npt_tginfo *npt = par->targinfo;
__sum16 src_sum = 0, dst_sum = 0;
__wsum src_sum = 0, dst_sum = 0;
unsigned int i;
if (npt->src_pfx_len > 64 || npt->dst_pfx_len > 64)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(npt->src_pfx.in6.s6_addr16); i++) {
src_sum = csum16_add(src_sum,
(__force __sum16)npt->src_pfx.in6.s6_addr16[i]);
dst_sum = csum16_add(dst_sum,
(__force __sum16)npt->dst_pfx.in6.s6_addr16[i]);
src_sum = csum_add(src_sum,
(__force __wsum)npt->src_pfx.in6.s6_addr16[i]);
dst_sum = csum_add(dst_sum,
(__force __wsum)npt->dst_pfx.in6.s6_addr16[i]);
}
npt->adjustment = csum16_sub(src_sum, dst_sum);
npt->adjustment = (__force __sum16) csum_sub(src_sum, dst_sum);
return 0;
}
@ -85,7 +66,7 @@ static bool ip6t_npt_map_pfx(const struct ip6t_npt_tginfo *npt,
return false;
}
sum = csum16_add((__force __sum16)addr->s6_addr16[idx],
sum = (__force __sum16) csum_add((__force __wsum)addr->s6_addr16[idx],
npt->adjustment);
if (sum == CSUM_MANGLED_0)
sum = 0;